interface Usb {
    public abstract void start();
    public abstract void stop();
}

class MoveDisk implements Usb {
    public void start() {
        System.out.printf("MoveDisk start....!\n");
    }

    public void stop() {
        System.out.printf("MoveDisk stop....!\n");
    }
}

interface Phone {

}

class iPhone implements Usb, Phone {
    public void start() {
        System.out.printf("iPhone start....!\n");
    }

    public void stop() {
        System.out.printf("iPhone stop....!\n");
    }
}

class Computer {
    public void InsUsb(Usb u) {
        u.start();
        u.stop();
    }
}

public class InterfaceTest {
    static public void main(String [] args) {
        Computer c = new Computer();

        c.InsUsb(new MoveDisk());
        c.InsUsb(new iPhone());

    }
}
